Macros defined using preference settings are expanded by enclosing the name in percent signs. Example:
When you write %WEBBGCOLOR%, it gets expanded to #FFD8AA
The sequential order of the preference settings is significant. i.e. set WEBCOPYRIGHT before WIKIWEBMASTER since %WEBCOPYRIGHT% uses the %WIKIWEBMASTER% setting.
You can introduce your own preference settings and use them in your topics and templates.